HUDSON, Fla. » When a Florida sheriff’s deputy responded to a 911 call of a shooting at a mobile home, he heard a chilling sound, a young, high-pitched voice screaming: "I’ve been shot. I’ve been shot."

What officers found inside the mobile home Wednesday was even more horrific, said Pasco County Sheriff Chris Nocco. A 12-year-old boy had shot his 6-year-old brother to death, wounded his older brother in the leg and then turned the gun on himself.

The older boys were cooking when an argument erupted. The boys’ mother, 38-year-old Helen Campochiaro, was out of the house at the time of the shooting, apparently working one of her two jobs.

"The mother’s going through an absolute living hell right now," Nocco said Thursday.

Nocco previously said the argument was over food, but a day later, he wouldn’t talk about it, saying only that the older boys were preparing food and deputies were still investigating.

The boys were identified as 12-year-old Kevin Pimentel, 6-year-old Brady Pimentel and 16-year-old Trevor Pimentel. They were home alone at the Sugar Lane Mobile Home Park north of Tampa while their mother was at work, Nocco said.

The sheriff refused to release many details about the crime, including the motive and where the boy got the gun, because he said deputies haven’t told the mother yet.

"She doesn’t yet know all the details," Nocco said. "She can’t handle that right now. She emotionally and physically can’t handle that right now."

Authorities said they have found no evidence that child welfare officials or police had ever been called to the home before the shooting.

Campochiaro was a hard-working woman who had two jobs so she could take care of her boys, the sheriff said. Campochiaro had been in a car wreck recently, but didn’t even go to the hospital because she had to work, Nocco said.

The boys’ 18-year-old brother also lived at the home, but he was not there at the time of the shooting.

Helen’s sister, Barbara Campochiaro, of Spring Hill, told The Tampa Bay Times the children "were raised with gun safety" and that Helen owned a firearm, though she was not sure what kind.

"She was a single mom with four boys. Unfortunately, she could only afford to live in a trailer," Campochiaro said. "She just had it (a gun) for protection."

Kevin was in middle school. Brady attended elementary school and Trevor took virtual high school classes at home in the mornings and culinary classes at a technical school in the afternoons.

Grief counselors were at the schools to talk to their friends, students and teachers.

Trevor is in the hospital, and is expected to be OK. When deputies tried to talk to him, his heart rate spiked.

"You’ve got a 16-year-old who just saw something horrific, a living nightmare. I would never want anyone to be in his shoes. He’s grieving right now. He just lost two brothers," Nocco said.

The family lived in the mobile home park off a dirt road in Hudson, which is about 30 miles north of Tampa on Florida’s Gulf coast.